Combine the cream cheese, butter, sugar, lemon juice, sour cream and cornstarch in the bowl and whip with electric hand mixie until mixed well but do not over beat the mixer.
Add the egg yolks one at a time and beat just until mixed. Beat the egg whites until stiff. Gently fold them in the cream cheese batter.
Pour the batter over the biscuit base. Wrap your spring form pan aluminium foil,
Place the springform pan into a larger pan and place into the oven. Fill with about 1 inch of hot water. The foil wrapped around the pan will prevent water from leaking inside.
Bake for 60-80 minutes or until the center is almost set.
Bake at 180 for 1 1/2 hours and let your cake cool in there for 30 minutes. After sometime keep the cake in the fridge to completely cool down for at least 6-8 hours, do not try to de mould.
Mix cornstarch, lemon juice, and warm water together in a small bowl until the cornstarch has dissolved.
Put blueberries and sugar together in a pan over medium heat. Stir continuously for 2-3 minutes until the blueberry juices begin to release.
Add the cornstarch mixture and continue to stir for another 2-3 minutes, crushing some blueberries. When the mixture will start to thicken remove from heat and keep it aside to cool.
When cheesecake is completely cooled and set, the center of cake will sink in middle the make prefect place to top blueberry sauce.